Steroids 76 (2011) 1419–1424

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Steroids

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Ecdysteroids from Polypodium vulgare L.

András Simon a, Attila Ványolós b, Zoltán Béni c, Miklós Dékány c, Gábor Tóth a, Mária Báthori b,⇑a Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, H-1111 Budapest, Hungaryb Department of Pharmacognosy , University of Szeged, Eötvös utca 6, H-6720 Szeged, Hungaryc Spectroscopic Research, Gedeon Richter Plc., Gyömr}oi út 19–21, H-1103 Budapest, Hungary

a r t i c l e i n f o a b s t r a c t

Article history:Received 3 February 2011Received in revised form 7 July 2011Accepted 13 July 2011Available online 22 July 2011

Keywords:EcdysteroidsPolypodium vulgareNMR

0039-128X/$ - see front matter � 2011 Elsevier Inc. Adoi:10.1016/j.steroids.2011.07.007

⇑ Corresponding author. Tel.: +36 62 545558; fax: +E-mail address: bathori@pharm.u-szeged.hu (M. B

Three new compounds (3, 7, and 11) together with eight known phytoecdysteroids (1, 2, 4–6, and 8–10)were isolated from the rhizomes of common polypody, Polypodium vulgare L. The structures of com-pounds were elucidated by spectroscopic methods including 1D and 2D NMR measurements. The 1Hand 13C NMR assignments of compounds 1, 6, 9 and 10 are included.

� 2011 Elsevier Inc. All rights reserved.

1. Introduction

Ecdysteroids were discovered as insect moulting hormones.However, they exist in almost all classes of arthropods and otherinvertebrate phyla, too. Analogues of the ecdysteroids, the phy-toecdysteroids are widely distributed secondary metabolites ofplants. They can be found in plant families comprising ferns, gym-nosperms and angiosperms [1]. The species Ajuga, Serratula andSilene possess highly diversified ecdysteroid spectra [2]. Thesecompounds display important physiological effects on insects suchas the regulation of moulting, metamorphosis and differentiation.Besides their involvement in the processes of metamorphosis in in-sects, they exert a wide range of biological activities. A number ofstudies have approved their effectiveness in enhancing proteinsynthesis in mammalian tissues with no negative hormonal conse-quences, which explains the widespread use of ecdysteroidsamong bodybuilders to increase the lean muscle mass, and alsoamong sportsmen to improve performance. These substances arenot regarded as prohibited doping substances, but their increasingusage with the aim of improved physical performance may forcethe authorities to change the status of these bioactive compounds.Ecdysteroids also exert other beneficial pharmacological propertieson mammals, such as decrease of the cholesterol level and glyca-emia in experimental animals, prevention arrhythmia, wound-healing activity, etc. [3].

Polypodium vulgare L. (common polypody) is a fern speciesfound in shaded, rocky habitats in Eurasia and North America.The traditional use of polypody in several European countries

ll rights reserved.

36 62 545704.áthori).

and among the native people in North America as an expectorantand laxative has been thoroughly documented in the scientific lit-erature. The polypody rhizome has also been applied as sweetenerin foods because of its content of sweet compounds. Eight ecdys-teroids have been described in common polypody so far, and wenow report the isolation and structure determination of 3 newecdysteroids, and of 8 known compounds of which 6 were foundin P. vulgare rhizome for the first time [4–8].

2. Experimental

2.1. General methods

Optical rotations were measured with a Perkin–Elmer 341polarimeter in MeOH. UV spectra were taken in MeOH with aShimadzu UV 2101 PC spectrophotometer. NMR spectra wererecorded in MeOH-d4 in a Shigemi sample tube at room tempera-ture with Bruker Avance DRX-500 and Varian VNMRS 800 spec-trometers. The structures of products were determined by meansof MS, in addition one- and two-dimensional NMR methods wereused [9,10]. Chemical shifts were given on the d-scale and werereferenced to the solvent (MeOH-d4: dC = 49.15 and dH = 3.31). Inthe 1D measurement (1H, 13C and DEPT-135), 64 K data pointswere used for the FID. The pulse programs of all experiments[gs-COSY, gs-HMQC-TOCSY (mixing time = 80 ms)], gs-HMQC;gs-HMBC, gs-NOESY (mixing times = 350 ms), ROESY (mixingtime = 250–350 ms), and 1D gs-NOESY (mixing time = 300 ms)]were taken from the Bruker and Varian software library.

HRMS analyses were performed on a LTQ FT Ultra (ThermoFinnigan, San Jose, CA) system. The ionization method was ESIand operated in positive ion mode. The ion transfer capillary

Table 113C chemical shifts of compounds 1, 3, 6-7, 9-11.

No. 1 3 6 7 9 10 11

1 34.3 34.3 34.4 37.5 37.9 37.9 33.02 68.5 68.5 68.6 68.9 29.9 29.9 76.43 70.3 70.4 70.4 68.7 77.6 77.6 68.14 36.3 36.3 36.3 33.0 27.3 27.4 35.85 80.6 80.4 80.4 51.9 54.4 54.4 80.46 202.2 202.6 202.5 * 202.6 202.6 *

7 121.2 120.6 120.7 122.2 123.6 123.6 120.98 164.4 167.3 167.7 167.7 167.2 167.2 *

9 39.8 39.3 39.2 35.6 51.4 51.4 39.110 45.7 45.6 45.5 39.5 39.6 39.7 45.911 21.8 22.7 22.6 21.7 23.0 23.0 22.412 25.2 32.3 32.5 32.2 40.1 40.1 32.713 54.2 48.3 48.4 48.5 46.1 46.1 48.614 80.4 85.0 85.2 85.2 56.5 56.5 85.215 29.2 32.2 31.8 32.3 23.8 23.8 31.816 34.1 27.1 21.9 27.3 28.2 28.2 21.617 220.0 48.9 51.9 49.5 54.3 54.3 50.618 17.7 16.3 18.3 16.3 12.8 12.8 18.219 17.3 17.1 17.1 24.6 13.6 13.6 16.920 43.6 77.1 39.3 41.6 41.5 78.021 13.4 20.8 13.1 14.4 14.4 21.222 75.4 85.7 82.2 #a #b 78.623 25.5 28.6 25.9 25.1 25.2 27.524 42.4 39.8 39.8 32.5 32.4 42.525 71.6 81.9 81.8 38.9 37.3 71.426 29.2 28.5 28.4 102.6 109.9 29.127 29.8 29.1 29.0 17.3 16.9 29.928 56.710 100.1 100.1 103.420 79.3 79.4 75.430 #a #b 78.040 72.0 72.1 71.850 77.9 77.9 78.260 63.0 63.0 62.9100 102.4 102.4200 72.4 72.4300 72.5 72.5400 74.2 74.2500 70.0 70.0600 18.2 18.1

* Below detection limit.a 79.6.b 79.4 or 79.5.

1420 A. Simon et al. / Steroids 76 (2011) 1419–1424

temperature was set at 280 �C as well as the capillary voltage was4.7 kV for each measurement. For CID experiment helium was usedas the collision gas, and normalized collision energy (expressed inpercentage), which is a measure of the amplitude of the resonanceexcitation RF voltage applied to the endcaps of the linear ion trap,was used to bring about fragmentation. The protonated molecularion peaks were fragmented by CID at a normalized collision energyof 35–40%. The samples were solved in a MeOH–H2O (1:1) + 1%(v/v) conc. AcOH solution. The compound 9 were diluted fromNMR solution (MeOH-d4), so the molecular ion and some frag-ments contained deuterium. Data acquisition and analysis wereaccomplished with Xcalibur software version 2.0 (Thermo ElectronCorp.).

HPLC analysis was performed with a Jasco Model PU-2080 Pump,Jasco Model UV-2070/2075 detector. A Zorbax-SIL column (5 lm,9.4 mm � 250 mm, DuPont, Paris, France) was used for normal-phase HPLC (2.5 ml/min flow, UV detection at 245 nm). Rotation pla-nar chromatography (RPC) was carried out on a Harrison Model8924 Chromatotron instrument (Harrison Research, Palo Alto, CA).The stationary phase for RPC was silica gel 60 GF254 (E. Merck).Column chromatographic support: Chemie Ueticon-C-Gel octadecylsilica (0.06–0.02 lm, Chemie Ueticon, Ueticon, Switzerland).

2.2. Plant material

Rhizomes were collected in October 2008 from three Hungarianlocations: environs of Veszprém, Egerbakta and K}oszeg. A voucherspecimen (collection number P71) has been deposited at theDepartment of Pharmacognosy, University of Szeged, Hungary.

2.3. Extraction and isolation

The dried rhizomes (1.4 kg) were extracted with MeOH, and theextract (254.1 g) was purified by precipitation, using acetone. Thedried residue of the filtrate (136.4 g) was further purified by parti-tion between aqueous MeOH and n-hexane. The dry residue of theaqueous MeOH phase (107 g) was applied to a polyamide column(MN-polyamide SC 6, Woelm, Eschwege, Germany). The fractionseluted with water (13.5 g), H2O–MeOH 9:1 (18.5 g) and H2O–MeOH 4:1 (9.7 g) were combined and subjected to low-pressurereversed-phase CC (C1). The fraction (0.94 g) eluted from re-versed-phase column (C1) with MeOH–H2O (2:3) was separatedby a combination of RPC (CH2Cl2–MeOH–C6H6 25:5:3 and EtOAc–EtOH–H2O 16:2:1) and normal-phase HPLC on silica to obtain com-pounds 1 (1.8 mg) and 2 (2.2 mg). The fraction eluted from C1 withMeOH–H2O (9:11) (0.39 g) was further purified by repeated RPC(CH2Cl2–MeOH–C6H6 25:5:3 and EtOAc–EtOH–H2O 16:2:1) andnormal-phase HPLC (CH2Cl2-i-PrOH–H2O 125:50:4) to give 3(1.5 mg). The fraction eluted from C1 with MeOH–H2O (1:1) wasseparated by repeated RPC (CH2Cl2–MeOH–C6H6, 25:5:3 andEtOAc–EtOH–H2O 16:2:1) and normal-phase HPLC (CH2Cl2-i-PrOH–H2O 125:50:4), which yielded 4 (1.8 mg) and 5 (1.2 mg).

Another fraction (0.44 g), eluted from C1 with MeOH–H2O(11:9), was separated by repeated RPC (CH2Cl2–MeOH–C6H6

25:5:3 and EtOAc–EtOH–H2O 16:2:1) and normal-phase HPLC(CH2Cl2-i-PrOH–H2O 125:30:2, in the first step and c-C6H12-i-PrOH–H2O 100:65:6 in the second step) to give compounds 6(1.2 mg), 7 (1.6 mg) and 8 (8.3 mg). The fraction (0.6 g) eluted fromC1 with MeOH-H2O (3:2) was purified by repeated RPC (CH2Cl2–MeOH–C6H6 25:5:3 and EtOAc–EtOH–H2O 16:2:1) and normal-phase HPLC (CH2Cl2-i-PrOH–H2O 125:65:6) to obtain 9 (3.4 mg),10 (2.2 mg) and 11 (0.9 mg).

2.3.1. 5-hydroxyecdysone (3)½a�28

D +31� (c = 0.1, MeOH); UV kMeOHmax (nm) (log e): 241 (3.84) 1H

and 13C NMR (MeOH-d4) (see Tables 1–3); ESI-MS m/z (relative

abundance (%)): 481 (0.1), 504 (30) [M+Na]+, 463 (1) [M+H–H2O]+, 445 (27) [M+H–2H2O]+, 429 (4) [M–2H2O–CH3]+, 427 (15)[M+H–3H2O]+, 409 (5) [M+H–4H2O]+, 393 (1), 363 (7) 345 (35),99 (100), 81 (32); HRESI-MS/MS: [M+H]+ = 481.3152 (calcd forC27H45O7, 481.3160, delta: �1.6 ppm).

2.3.2. 20-deoxyshidasterone (7)½a�28

D +12� (c = 0.1, MeOH); UV kMeOHmax (nm) (log e): 242 (3.72) 1H

and 13C NMR (MeOH-d4) (see Tables 1–3); ESI-MS/MS m/z (relativeabundance (%)): 447 (0.1), 429 (100) [M+H–H2O]+, 411 (12) [M+H–2H2O]+, 393 (4) [M+H–3H2O]+, 375 (1) [M+H–4H2O]+, 331 (11);HRESI-MS/MS: [M+H]+ = 447.3105 (calcd for C27H43O5, 447.3105).

2.3.3. Polypodosaponin (9)½a�28

D �37� (c = 0.1, MeOH); UV kMeOHmax (nm) (log e): 244.2 (2.36)

1H and 13C NMR (MeOH-d4) (see Tables 1–3); ESI-MS/MS m/z (rel-ative abundance (%)): 658 (2) [M�H + D + Na–C4H8O3]+, 642 (3)[M�H + D + Na–C4H8O4]+, 616 (100), 598 (3), 331 (2) [C12H20O9Na];HRESI-MS: [M+H]+ = 739.4236 (calcd for C39H63O13, 739.4263, del-ta: �3.6 ppm).

2.3.4. 26-methoxypolypodosaponin (10)½a�28

D �10� (c = 0.1, MeOH); UV kMeOHmax (nm) (log e): 245 (2.06) 1H

and 13C NMR (MeOH-d4) (see Tables 1–3); ESI-MS/MS m/z (relative

Tabl

e2

1H

chem

ical

shif

tsan

dch

arac

teri

stic

coup

ling

cons

tant

sof

the

fuse

dri

ngsk

elet

onof

com

poun

ds1,

3,6–

7,9–

11.

No.

13

67

910

11

dJ

(Hz)

dJ

(Hz)

dJ

(Hz)

dJ

(Hz)

dJ

(Hz)

dJ

(Hz)

1a

1.74

1.74

1.73

1.80

a:1.

42a:

1.44

a:1.

82b

1.74

1.74

1.73

1.43

dd;

13.3

,12.

5b:

1.86

b:1.

87b:

1.90

2a

3.94

ddd;

8.7,

8.3,

3.3

3.95

ddd;

9.5,

6.9,

3.5

3.94

3.84

a:1.

46a:

1.44

4.15

ddd;

12.1

,4.8

,3.5

bb:

1.90

b:1.

893

a4.

00q;

3.1

3.99

q;3.

03.

993.

95q;

2.9

3.80

tt;

11.3

,4.3

3.81

tt;

11.2

,4.4

4.21

q;3.

04

a2.

07dd

;14

.8,3

.02.

08dd

;14

.8,3

.02.

07a:

1.70

a:1.

39a:

1.40

2.08

dd;

14.9

,3.0

b1.

801.

771.

77b:

1.75

b:2.

33b:

2.33

1.81

5a

2.35

2.35

b5.

852.

39dd

;12

.8,4

.67

5.97

d;2.

85.

86d;

2.7

5.82

d;2.

65.

67t;

2.1

5.67

t;2.

25.

85d;

2.7

9a

3.22

ddd;

11.5

,6.9

,2.8

3.19

3.19

3.15

2.31

2.31

3.20

11a

1.92

dddd

;13

.6,6

.7,4

.8,2

.1a:

1.74

1.81

1.81

a:1.

69a:

1.69

1.92

b1.

71dd

d;13

.6,1

1.6,

4.9

b:1.

821.

751.

67b:

1.86

b:1.

871.

7212

a2.

13td

;13

.2,4

.82.

132.

152.

11td

;13

.0,4

.9a:

1.49

a:1.

492.

13td

;13

.1,5

.0b

1.59

ddd;

13.0

,4.9

,2.0

1.79

1.86

1.79

b:2.

17b:

2.18

1.89

14a

2.18

2.18

15a

2.02

1.60

1.60

1.60

a:1.

56a:

1.59

1.60

b2.

301.

971.

961.

98b:

1.68

b:1.

691.

9616

a2.

361.

52a:

1.81

1.52

a:1.

47a:

1.49

1.73

b2.

511.

97b:

2.00

1.98

b:1.

89b:

1.89

1.99

17a

2.02

2.36

1.94

1.43

1.44

2.39

18b

0.88

s0.

74s

0.85

0.74

s0.

67s

0.68

s0.

90s

19b

0.94

s0.

92s

0.91

0.97

s0.

88s

0.88

s0.

93s

A. Simon et al. / Steroids 76 (2011) 1419–1424 1421

abundance (%)): 671 (2) [M+Na–C4H8O3]+, 655 (3) [M+Na–C4H8O4]+, 629 (100), 331 (1) [C12H20O9Na] +; HRESI-MS: [M+H]+ =753.4420 (calcd for C40H65O13, 753.4420).

2.3.5. Polypodine B 2-b-D-glucoside (11)½a�28

D + 13� (c = 0.1, MeOH); UV kMeOHmax (nm) (log e): 238 (3.83) 1H

and 13C NMR (MeOH-d4) (see Tables 1–3); ESI-MS/MS m/z (relativeabundance (%)): 497 (100) [M+H–C6H10O5]+, 479 (9)[M+H–C6H10O5–H2O]+, 461 (33) [M+H–C6H10O5–2H2O]+, 443 (17)[M+H–C6H10O5–3H2O]+, 425 (1) [M+H–C6H10O5–4H2O]+, 387 (1),363 (1); HRESI-MS/MS: [M+H]+ = 659.3639 (calcd for C33H55O13,659.3637, delta: 0.3 ppm).

3. Results and discussion

The isolation of compounds 1–11 from the methanolic extract in-volves fractionated precipitation and combined chromatographicprocedures, including CC on polyamide and octadecyl silica,RPC and preparative HPLC. The compounds 2 [2,11], 4 [2,12], 5[2,13] and 8 [2,14] were identified by comparing their chromato-graphic and spectroscopic data with those of authentic samples.The structures of compounds 1, 3, 6, 7 and 9–11 (Fig. 1) were eluci-dated by using NMR, UV and MS measurements. Since of compounds1, 6, 9 and 10 only some 1H-NMR data were available in the literature[2,6,15,16] here in, all the 1H and 13C NMR data of these compoundsare given in the Tables 1 and 2.

The UV spectra of these compounds proved the presence of anenone moiety.

On the basis of the protonated molecular ion peak observed byHRESI-MS/MS the molecular formula of 3 was C27H44O7, 7 wasC27H42O5, 9 was C39H62O13, 10 was C40H64O13, while 11 wasC33H54O13. In most cases the characteristic fragment ions wereformed from the protonated molecular ion by the loss of sugarunits, and some fragments of sugars and water.

The 1H and 13C NMR data of the compounds 1, 3, 6–7 and 9–11are summarized in Tables 1–3.

Due to our long-time intense research interest in the structureelucidation of ecdysteroids we were able to set up a complete data-base containing the characteristic 1H and 13C chemical shifts, 1Hmultiplicity and couplings constants of the earlier investigatedcompounds. The 1H, 13C and HMQC correlations of compound 6and our data on polypodine B and shidasterone allowed us to elu-cidate the structure of compound 6 as ajugasterone D. Consideringour database we concluded that the fused ring skeletons of com-pounds 3 and 7 are the same as in polypodine B and in 20-hydrox-yecdysone, respectively. In addition the side chain of compound 11is identical with that of 20-hydroxyecdysone.

At first characteristic HMBC correlations over two and threebonds of methyl signals and the olefinic hydrogen (H-7) were uti-lized in the assignment. The H3-18/C-14, H-7/C-14, H-7/C-5, H-7/C-9, H3-19/C-1, H3-19/C-5 and H3-19/C-9 HMBC correlations resultedin the assignment of Me-18 and Me-19 groups. The H3-18/C-17 andH3-21/C-17 cross-peaks identified Me-21 signals. The H3-26/C-27and H3-27/C-26, furthermore the H3-26/C-25 H3-26/C-24, H3-27/C-25 and H3-27/C-24 HMBC correlations made possible the identi-fication of the geminal Me-26/Me-27 methyl groups in compounds3, 6, 7 and 11 [17–18]. These correlations are characteristics of C27-ecdysteroids. The hydrogen atoms of ring A as well as rings B, C, D,side-chain and sugar units form separated spin systems that wereanalysed by z-filtered-TOCSY, 1H,1H-COSY and HMQC-TOCSYexperiments.

The characteristic H-26/C-22 cross-peak observed in the HMBCspectrum of compound 9, the H-26/H-22 responses in the ROESYspectra of compounds 9 and 10, respectively, moreover thechemical shift of the C-26 signal of 9 (d 102.6) and 10 (d 109.9)

Table 31H chemical shifts and characteristic coupling constants of the side chain of compounds 3, 6–7, 9–11.

No. 3 6 7 9 10 11

d J (Hz) d d J (Hz) d J (Hz) d J (Hz) d J (Hz)

20 1.76 1.85 1.78 1.7921 0.95 d; 6.7 1.21 0.935 d; 6.5 1.01 d; 6.8 1.01 d; 6.7 1.197 s22 3.59 3.91 4.11 ABX 3.48 3.45 3.3223 a 1.32 1.75 1.79 1.32 1.30 qd; 12.5, 3.4 1.29

b 1.55 1.89 1.79 1.43 1.43 d; 12.5 1.6624 a 1.41 1.75 1.75 1.19 1.20 qd; 12.5, 3.4 1.44

b 1.80 1.75 1.75 1.82 1.82 d; 12.5 1.8025 1.31 1.3526 1.19 s 1.24 1.246 s 4.24 d; 8.3 3.95 d; 8.5 1.19 s27 1.21 s 1.25 1.246 s 0.92 d; 6.5 0.89 d; 6.8 1.202 s28 3.44 s10 4.55 d; 7.7 4.55 d; 7.8 4.45 d; 7.820 3.37 dd; 9.3, 7.8 3.37 3.23 dd; 8.8, 7.930 3.48 t; 9.1 3.49 3.38 t; 9.040 3.26 3.26 3.3250 3.26 3.26 3.3160 a 3.65 3.64 3.70 dd; 11.8, 5.3

b 3.85 3.86 3.89 dd; 12.0, 1.8100 5.19 d; 1.6 5.19 d; 1.7200 3.94 dd; 3.3, 1.8 3.93 dd; 3.4, 1.7300 3.73 dd; 9.5, 3.3 3.72 dd; 9.6, 3.4400 3.37 3.37500 4.13 4.13 dq; 9.6, 6.2600 1.24 d; 6.3 1.24 d; 6.2

1422 A. Simon et al. / Steroids 76 (2011) 1419–1424

were evidences of a cyclic hemiacetal between C-22 and C-26 inboth compounds.

The HMBC cross-peak of H-10/C-2 in compound 11 resulted theposition of the sugar moiety. The H-10/C-3, H-20/C-100, H-100/C-20

correlations in compounds 9 and 10 proved the C-3 connectionof the disaccharide units to the aglycone. The z-filtered 1D-TOCSYgave the couplings constants of hydrogens in sugar moieties andthis way we could identify the sugar units marked by 0 in Tables1–3 as b-D-glucose and sugar units marked by 00 in Tables 1–3 asL-rhamnose. H-200 in rhamnose has an equatorial position thusthe axial a- or equatorial b-position of H-100 could not be givenfrom the value of 3J (H-100/H-200) coupling constant. To overcomethis uncertainty, the 1J(H-100/C-100) couplings were utilized, whichwere detected by the 13C-coupled HMQC experiments. It is wellknown that, owing to the lone-pair effect, an antiperiplanararrangement of the lone-pair on the ring oxygen atom with respectto the anomeric C-H bond (axial hydrogen), the characteristic valueis about 160 Hz, i.e. 10 Hz less than in the anomeric pair (equato-rial hydrogen) [19,20]. For the glucose moiety in compound 9 themagnitude of 1J(H-100/C-100) was measured 160 Hz, whereas thecorresponding value for the rhamnose was 173 Hz. It unequivo-cally proves the presence of a-L-rhamnose moiety.

The coupling constants of H-2 signal and the H-2/H-9 NOESY re-sponse of compounds 1, 3, 7 and 11 supported the cis A/B ring junc-tion moreover the b-orientation of the OR substituent. Thecoupling constants of H-3 signal and H-3/H-5 cross-peaks inNOESY and ROESY spectra of compounds 9 and 10 indicated thetrans A/B ring junction in both compounds. A further support ofthe trans type ring junction can be gained from the chemical shiftsof C-19 (13.6 ppm in both compounds) which characteristicallydiffer from the measured value for 20-hydroxyecdysone(24.4 ppm) [2]. We have earlier reported similar C-19/C-2 and C-19/C-4 c-gauche interactions in analogous trans A/B typederivatives [18]. In compounds 1, 3, 7, and 11 Hb-12/H3-18,Ha-12/Ha-17, H3-18/Hb-15 and H3-18/Hb-16 NOESY cross-peaksrevealed the trans C/D ring junction. It is known that the C-12and C-15 chemical shifts show significant differences between20-hydroxyecdysone (32.5 and 31.8 ppm) and in the isomeric14-epi-20-hydroxyecdysone (41.7 and 40.8 ppm) [2]. In case of

3, 7 and 11 we measured: �32.2; 31.2 and 32.7 ppm chemicalshifts for C-12, whereas the C-15 signals were detected at �32.2;32.3 and 31.8 ppm. These chemical shifts gave a further strong evi-dence for the trans junction of C/D rings. We have earlier reported[21] the structure elucidation of two analogous 14-H-epimers. Thechemical shifts of C-14 and C-15 were 59.2 and 34.1 ppm, respec-tively, for the Hb-14 epimer and 57.2 and 23.6 ppm, respectively,for the Ha-14 epimer. A comparison with the chemical shifts ofC-14 (56.5 ppm) and C-15 (23.8 ppm) of 9 and 10 indicated a goodconcordance with those of the Ha-14 epimer.

The configuration of C-20 and C-22 stereogenic centers pro-posed for 3, 6 and 11 were deduced the by close similarity of theirNMR spectra with those of in compounds 3, 6 and 11 could besuggested on the basis of close similarity of 13C chemical shiftsmeasured in these compounds and the reference compounds(ecdysone, shidasterone and 20-hydroxyecdysone, respectively)[2,14]. In case of compounds 9 and 10 the configuration of stereo-genic centers of the steroid skeleton including also C-20 are known[2] but the configuration in pyranose unit is not definied. The rel-ative configuration of tetrahydropyrane moiety in 9 and 10 wasstudied by one-dimensional selective z-filtered TOCSY experiment.The measured values of 3J(H-26/H-25) � 8.5 Hz indicate the axial-axial arrangement of these protons. The 3J(H-22/Ha-23) � 3J(Ha-23/Ha-24) � 3J(Ha-24/H-25) � 11 Hz coupling constants elucidated thechair conformation of the tetrahydropyrane ring, moreover theequatorial position of the C-20 atom. The substituents in positions22, 25 and 26 are equatorial arranged which can be correlated with22-S, 25-R, 26-R or 22-R, 25-S, 26-S configurations. It should bementioned that we failed observing high resolved H-22 signalbut the 1H spectrum and the corresponding cross-peak in theHMQC spectrum indicate only one coupling with the value of�12 Hz. On this basis we can conclude that H-20 and H-22 atomsare gauche located in the preferred conformation around theC-20–C-22 bond. Further information on the predominating con-formation can be gained considering the NOE responses betweenH3-21/Hb-12, H3-21/H3-18 and H3-21/H2-23. This measurementrevealed there is no steric proximity between H3-21/H2-16 andHb-12/ H2-23. Such sterical arrangement could be explained with22-S, 25-R, 26-R but we do not have unambiguous exact proofs

HO

HOMe

O

OHH

OH

OMe

1

5

10

8

11 1314

1719

18

HO

R1OMe

O

OH

Me

H

OH

Me

Me

OH

OH

Me

R2

1

5

10

11

8

1314

17

20 25

2

H

1 3 11

R1 H Glu

R2 H OH

HO

HOMe

O

OHH

OH

Me

O MeMe

MeOH

1

5

10

8

11 1314

17

19

18 20

21

22

25

H

HO

HOMe

O

OHH

H

Me

O MeMe

Me

1

5

10

8

11 1314

17

19

18 20

21

22

25

H

6 7

Me

Me

H

O

OH

H

Me

OMe

OR

Rha-Glu

1

3 5

10

11 13

814

17

2022

2625

H

9 10

R H Me

Fig. 1. Structures of compounds 1, 3, 6–7 and 9–11.

A. Simon et al. / Steroids 76 (2011) 1419–1424 1423

for the exclusion the alternative 22-R, 25-S, 26-S configurations. Asimilar compound to 9 and 10 is Polypodoside A [22,23], where in-stead of R = H, Me the substituent is a rhamnopyranosyl(rha-1 ? C-26) moiety. The determined 20-S, 22-R, 25-S and26-R configurations correlate well with our 20-S, 22-R, 25-S and26-S configurations in compounds 9 and 10. It should be men-tioned that the introduction of a rhamnopyranosyl moiety resultedthe change of configuration at C-26.

Unfortunately, H-22 is a part of ‘‘X’’ of a higher ordered spinsystem of H-17/H-20 and H2-23 in compound 7 prohibiting theutilization of 3J(H/H) couplings to sterical analysis. On this waywe should leave the configuration of C-20 and C-22 unresolved.

The ecdysteroids 1, 2, 4–6, 8 are reported for the first time fromP. vulgare. C-5 is the characteristic hydroxylation position of

ecdysteroids from common polypody: several of the isolatedecdysteroids possess a 5-OH group [2]. The common occurrenceof basic ecdysteroid compounds together with their corresponding5-OH compounds proves that the final hydroxylation step occurs atC-5, in accordance with an earlier hypothesis [24]. Compound 3 is anew, 5-hydroxylated ecdysteroid which is present in the plant to-gether with the parent compound, ecdysone.

The characteristic ecdysteroids of P. vulgare have a side-chain intheir molecule, which forms intramolecular ether or a hemiacetal-containing ring. In three ecdysteroids with a cyclic ether functionin the side-chain, shidasterone (8) and shidasterone derivatives(6–7), the 22-OH group forms intramolecular ether linkage withthe 25-OH group. The ecdysteroids with a cyclic ether function inthe side chain are typical plant ecdysteroids. Other representatives

1424 A. Simon et al. / Steroids 76 (2011) 1419–1424

of these rare ecdysteroids have been isolated so far mainly fromAjuga, Leuzea, Serratula and Vitex species and from one fungusand one fern species [2]. We report the isolation of a new naturalcompound with a cyclic ether function, compound 7, which waspreviously synthesized from 20-hydroxyecdysone by Rousselet al. [25].

Ecdysteroids containing a hemiacetal function in their-sidechain are currently known to occur only in Polypodium species.Their glycosidic forms exhibit sweetness intensity much higherthan that of sucrose. Such a well-known compound is osladin,which together with other structures can be regarded as potentialalternatives to sucrose [5]. These low hydroxylated ecdysteroidsare glycosylated at C-3 and/or C-26 and have the rare trans A/B ringjunction. In these compounds C-26 forms an internal hemiacetalring with the OH group at C-22. Compounds 9 and 10 possess sucha structure; the former was isolated earlier from P. vulgare and wasnamed polypodosaponin. Jizba et al. [6] reported that 10 is an arti-fact arising from 9 by the methylation of 26-OH during theisolation.

We have additionally isolated another new glycoside, the 2-glucopyranoside of polypodine B (11), which is the third exampleof a C-2 glucosyl derivative among the ecdysteroids.

Acknowledgments

The authors thank Dr. J. Cservenka (Balaton Uplands NationalPark, Hungary), J. Sulyok (Bükk National Park, Hungary) and B.Kóródi (}Orség National Park, Hungary) for their help in the identi-fication and collection of plant material. This investigation wassupported by the New Development Plan TÁMOP-4.2.2-08/1-2008-0013 and TÁMOP-4.2.1/B-09/1/KONV-2010-0005.

Appendix A. Supplementary data

Supplementary data associated with this article can be found, inthe online version, at doi:10.1016/j.steroids.2011.07.007.

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